The Program's broad long-term objective is to develop new targeted therapeutics for acute myelogenous leukemia (AML). The overarching hypothesis of the Program Project is that sphingolipid metabolism is altered in AML and can be used to direct therapeutic regimens. A corollary of this hypothesis suggests that novel therapeutics that target dysfunctional sphingolipid metabolism may be highly efficacious in AML. The integration of the Program follows the metabolism of ceramide. Project 1 targets ceramide metabolism utilizing ceramide-based nanotherapeutics; Projects 2 and 3 target acid ceramidase and sphingosine kinase, which coordinately generate the pro-mitogenic and anti-apoptotic ceramide metabolite, sphingosine- 1-phosphate, and Project 4 targets P-glycoprotein-mediated glycosylation of ceramide. All Projects have validated therapeutic modalities in both in vitro and in vivo models of AML. The Program is supported by five integral Cores. These include the: Synthesis and Nanoformulation Core, which provides synthesized compounds not available commercially for biologic studies; Targeted Sphingomics Core, which is essential for quantification of sphingolipid metabolism; Animal Modeling and Clinical Resources Core, which provides state-of-the-art molecularly defined AML samples with annotated clinical outcomes and murine leukemia stem cells models; Biostatistics Core, which provides critical research design and analysis; Administrative Core, which provides oversight and coordination of all scientific, administrative, and fiscal activities. Development of targeted therapeutics for AML will be pursued in the following overall Specific Aims of the Program: 1. Engineer, characterize and optimize novel lipomimetic- or small molecule-based therapeutics for AML. 2. Validate the efficacy and toxicology of sphingolipid-targeted therapeutics in vivo using murine leukemia stem cells models. 3. Define the role of altered sphingolipid metabolism in cell survival, apoptosis, autophagy, and drug resistance in AML. To accomplish these Aims, we have assembled a transdisciplinary team of clinical and basic scientists, organic chemists, and material scientists. We are fortunate that NCI NanoCharacterization Laboratory has accelerated pre-clinical development of the Penn State ceramide liposomal nanoplatform. The clinical significance of the Program rests on the urgent and unmet needs for development of new therapeutics in AML. In the revised application, we have specifically responded to all of the reviewer's critiques, in particular, addressing the major issues associated with AML heterogeneity and humanized AML murine models. Importantly, we have documented engraftment in NSG mice of AML subsets defined by integrated genetic profiling.